Dynamic analysis for clarifying occlusal force transmission during orthodontic archwire application: difference between ISW and stainless steel wire

The purpose of our study was to utilize thedynamic finite element analysis to clarify the differencebetween Improved Super-elastic Ti-Nialloy Wire (ISW) and Stainless Steel Wire (SSW) onocclusal force transmission during orthodontictreatment. ABAQUS/Standard was used to analyzethree finite models over a 30-ms period: ISW,SSW, and wireless models; which consisting ofpremolar, molar, periodontal ligament (PDL), andalveolar bone. Wire model was established bybeam element. A Joint C, which exhibits viscoelasticityto buffer occlusal force, was appliedbetween the wire and bracket. The load wasapplied on the occlusal surface. At load withdrawalpoint, the average amounts of von Mises stresson PDL in three models were of the same value.However as time progressed, the stress in wirelessmodel became higher than ISW and SSW models.In contrast, as time progressed further, the stressin SSW model became higher than the other twomodels and maintained its higher level until the endof analysis. Results showed that high dampingcapacity of ISW had an ability to buffer the transmissionof occlusal force to the PDL. Besides, thedynamic analysis demonstrated an advantage toinvestigate the stress alterative response betweenmodels versus time period.